Posted on 08/18/2007 12:28:58 AM PDT by yorkie
A national mine safety expert believes the two collapses at the Crandall Canyon Mine [snip] were caused by "bumps" that resulted from the way operations were being conducted at the Huntington mine. Mining bumps are pressure-shifting seismic events than can cause the walls, pillars, ceiling and even the floor of a mine to literally explode and disintegrate. They can cause deaths and injuries, and can result in cave-ins. [snip] And while an investigation ultimately will determine the cause, Ferriter told the Deseret Morning News on Friday he feels certain the bumps were caused by mining activity.
"In my opinion, based on the evidence and the way it's described, I think it definitely was a mining-induced bump," he said of the initial Aug. 6 collapse.
[snip]"Earthquakes happen naturally. Bumps are a coal-mining phenomenon," Ferriter said, adding that bumps are more severe in Utah mining because thick (as much as 300 feet), heavy beds of sandstone often exist above mining operations, placing a great deal of stress on the man-made caves beneath them.
[snip]Ferriter said it is his understanding that around the time of the Aug. 6 collapse, miners had been extracting coal from the pillars themselves.
"Often, it's when you try and take too much of the pillar" that bumps occur, he said. "I understand they were retreating out of that section and taking some of that pillar out on the way out, maybe shaving it or splitting the pillar to get the coal. The more you take, the greater the load on the rest of the pillar."
And that is what may have led to the Aug. 6 bump, which registered 3.9 on the Richter scale.
"That's my opinion. (Miners were) taking too much" of the pillar, Ferriter said.
(Excerpt) Read more at deseretnews.com ...
The reporting on this whole event has been very irritating. So little technical information is being reported properly, so it’s not even clear what the operations actually were.
That giant sucking sound you hear is an army of lawyers invading Utah.
The mine owner is trying too hard to sell the natural earthquake cause. He is in cover your six mode.
And I agree with him. All one need do is see all the "aftershocks" to know it was an earthquake that caused this. I bet they don't find at least 15 cave-ins to explain the aftershocks.
What do you expect? Journalists are people who didn't have the brains to study science or engineering in college.
I have seen an area where pillars had been pulled 40 years before and the stresses on the rock that was left did astonishing things. The floor heaves up in arches, the pillars bow out. It is spooky. Could you imagine a whole field of pillars just crushing in an instant? Ouch!
Finally someone here on FR understands what is going on. Great comment.
I have looked at the mine maps where the ‘event took place’. IMSHA approved Murray’s plan. I just hope he followed the plan. Imagine looking down on a map with two blocks of coal, 1000 feet wide, seperated by a 300 ft. barrier plus development of 150 feet in the main entry. This is one side and the other is the same with the mains in the middle. So you have the mains in the middle (~150 ft) 300 ft. of barrier on each side and 1000 ft. of mined out longwall (gob) caved in material on each side of the mains.
They were permitted as I understand to pull some of the supporting pillars next to the mains along with mining into the 300 ft barrier on each side.
You are correct with your remarks. This is high coal with a lot of cover (mountain on top).
I pray that Murray followed the approved mine plan.
One other note, the ribs are exploding not the top. There is a very thick seam of limestone strata supporting the roof. That is why the rib is blowing out. A natural bomb without the fire.
As well he should be to get the mine back in operation. Miners are just as tough as those who deliver pizza in Detroit.
Oh...?
My wife received a National Merit Scholarship to attend university, where she majored in physics and minored in math. Her graduate studies were in chaos theory and mathematical modeling of the atmosphere, though that's just from trusting what she tells me--her publications seem like just a bunch of equations. :-)
And...she's a damn good newspaper editor-in-chief, with awards both for herself and her staff's work.
OTOH, you might be close to the truth...I think that we scientists are those who didn't have the brains (and ethics deficit) to just go into something unproductive, like spurious tort-law litigation.
You’re not insinuating that your wife is the norm in journalism i.e. Physics major?
He’s in an airplane?
The 10 most dangerous jobs by fatality rate are: Top of page Rank Occupation Death rate/100,000 Total deaths 1 Logging workers 92.4 85 2 Aircraft pilots 92.4 109 3 Fishers and fishing workers 86.4 38 4 Structural iron and steel workers 47.0 31 5 Refuse and recyclable material collectors 43.2 35 6 Farmers and ranchers 37.5 307 7 Roofers 34.9 94 8 Electrical power line installers/repairers 30.0 36 9 Driver/sales workers and truck drivers 27.6 905 10 Taxi drivers and chauffeurs 24.2
Forgive me for a generalization.....
She learned more and more about less and less till she knew nothing about anything.
From http://en.wikipedia.org/wiki/Retreat_mining
Retreat mining is a term used to reference the final phase of an underground mining technique known as Room and pillar mining. This involves excavating a room, or chamber while leaving behind pillars of material for support. This excavation is carried out in a pattern advancing away from the entrance of a mine. Once a deposit has been exhausted using this method, the pillars that were left behind initially are removed, or ‘pulled’, retreating back towards the mines entrance. After the pillars are removed the roof (or back) is allowed to collapse behind the mining area. Pillar removal has to occur in a very precise order in order to reduce the risks to workers, due to the high stresses placed on the remaining pillars by the abutment stresses of the caving ground.
Retreat mining is the term commonly referred to as the mining method employed by the Crandall Canyon Mine and is believed, by some, to be a factor in the August 2007 collapse which trapped six miners. As of August 17, 2007, the ultimate fate of the trapped miners is unknown. Robert E. Murray, CEO of Murray Energy says the technique was not being used at Crandall Canyon.
When we first heard this story, the cause was reported to be an earthquake; then it became a “siesmic event”; then it became a “bump”; then it became a “mine accident” caused by the mining itself. It seems like the “government scientists” who spout this stuff are being prepped on what to say by politicians/bureaucrats in the backgroung. Naturally, somebody has to be blamed...and you can’t hold Mother Nature accountable, can you??
In the US initial reports are computer-automated, and EVERYTHING gets reported as an earthquake - even quarry blasts (you'll see the quake removed after a human examines the data - I've seen it many times.
The computer isn't "smart" enough to distinguish a mine collapse from an earthquake. After a sesimologist examined the data it was pretty clear what it was.
This is obvious to me, but the obsessive hatred of scientists and science on FR seems to be growing exponentially.
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